The locus and nature of the choleragen and endotoxic lipopolysaccharide effects on steroid secretion by adrenal cells in culture has been studied by the use of mutant cell lines, receptor competition and the use of gangliosides. The receptor for ACTH has a different locus than those for these toxins. In addition the role of adenosine-containing compounds in steroidogenesis and adenylate cyclase activation has been elucidated. For all stimulators the effect appears to be on the external surface of the cell membrane via activation of adenylate cyclase.